Silhouettes have limited functionality. They tell a simple story through body language and not through expressions. They have a limited role in photography but they complement a set of photos where you can see the subjects facial expressions. I love silhouettes because they are so dramatic and you can only tell one story. Usually just the sky and the people, you can’t get much simpler than that! People that have a good figure can also benefit from silhouettes because it really shows off your shape. I will often have couples face each other so I can see the profile of their face.